Jonne Rodenburg
Dr Jonne Rodenburg, is a Professor of Agronomy at the Natural Resources Institute (NRI) of the University of Greenwich in the UK where he is Leader of the Sustainable Agricultural Intensification Programma and Deputy Leader of the Ecosystem Services Research Group. He is also Associate Editor of Field Crops Research and a subject editor of Weed Research. Jonne's research work focusses on two main research topics: (1) biology, ecology and management of weeds and parasitic weeds in cereal-based cropping systems, and (2) sustainable agricultural and natural resource management in smallholder farming systems. His main objective is to develop sustainable, affordable and socially acceptable management strategies for smallholder farmers in sub-Saharan Africa (SSA). He has published 7 peer-reviewed book chapters, 60+ conference papers and 70+ Science Citation Indexed (SCI) peer-reviewed journal articles. His Scopus H-index is 28 .
Address: NRI
Medway Campus
Central Avenue
Blake building
Chatham Maritime
ME4 4TB
Address: NRI
Medway Campus
Central Avenue
Blake building
Chatham Maritime
ME4 4TB
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We conducted mini-rhizotron assays to investigate the effects of macronutrient and micronutrient availability on post-germination Striga development. Four sorghum genotypes (Framida, IS10978, N13, IS9830) covering the complete array of known mechanisms of post-attachment resistance were compared with susceptible genotype Ochuti. Plants were infected with pre-germinated Striga seeds and subjected to four nutrient treatment levels: (1) 25% of the optimal concentration of Long Ashton solution for cereals; (2) 25% macronutrient and optimal micronutrient concentration; (3) optimal macronutrient and 25% micronutrient concentration; and (4) optimal macronutrient and micronutrient concentrations.
Compared with the 25% base nutrient level, treatments supplemented with macronutrients reduced the number of viable vascular connections established by pre-germinated Striga seedlings as well as the total parasite biomass on the sorghum root system. Macronutrient treatment effects were observed across sorghum genotypes, independent of the presence and type of post-attachment resistance, but appeared to specifically improve mechanical resistance, hypersensitive and incompatibility responses before Striga reaches the host-root xylem.
This study demonstrates, for the first time, that nutrient availability drives Striga parasitism beyond the germination stages. Increased availability of nutrients, in particular macronutrients, enhances host-plant resistance in post-attachment stages, reinforcing the importance of current fertiliser recommendations.
smallholders, women and youth to benefit from SAI. While some tools and
processes are presented that may support this, there remains a challenge as to how such processes can be integrated into national policies and institutions.
with some proposing that only an ‘agroecological’ intensification pathway delivers sustainability. Others take a broader perspective arguing that all aspects of ecological, genetic, and socio-economic intensification need to be considered, but then assessed in terms of the sustainability of the outcomes. A major concern is that intensification that focuses on agricultural technology can lead to inequitable outcomes for women and poorer households, while agroecological intensification building upon local capitals is generally considered more equitable. Understanding the potential outcomes and inherent trade-offs of different approaches requires interdisciplinary research, evidence and decision-making tools, some examples of which are presented in this Special Issue
In all CA practices S. asiatica infection was significantly reduced. Best results were obtained with Stylosanthes guianensis (CAST). This species also suppressed ordinary weeds much better than other cover crops. With CAST, average parasite emergence was delayed by 7.5 days (in rice) and 6.3 days (in maize) and infection levels were reduced by 79% (in rice) and 92% (in maize) compared to the conventional farmer practice (CONV). NERICA varieties delayed S. asiatica emergence by 5.7 days (NERICA-9) and 9.7 days (NERICA-4) and reduced infection levels by 57% (NERICA-9) and 91% (NERICA-4) compared to B22. In maize the residual effect of resistance of NERICA-4 resulted in a delay of 7.5 days in S. asiatica emergence and a reduction of 60% in parasite numbers. The best combinations delay S. asiatica emergence by 17.8 days (CAST + NERICA-9) and 19.1 days (CARB + NERICA-4) and reduce the parasite infection levels by 96% (CAST + NERICA-9 or -4) to 98% (CARB + NERICA-4) in rice, compared to CONV + B22. After two full rice-maize rotation cycles S. asiatica seed numbers in the soil (0-10 cm) were 76% (CACM), 78% (CAST) and 86% (CARB) lower than under CONV. Even the combination of zero-tillage, crop residue mulching, cover crops and resistant rice varieties does not entirely prevent S. asiatica parasitism and seed bank increase. Additional measures, targeted to escaping weeds, would be required for fully effective and long-term control.
We conducted mini-rhizotron assays to investigate the effects of macronutrient and micronutrient availability on post-germination Striga development. Four sorghum genotypes (Framida, IS10978, N13, IS9830) covering the complete array of known mechanisms of post-attachment resistance were compared with susceptible genotype Ochuti. Plants were infected with pre-germinated Striga seeds and subjected to four nutrient treatment levels: (1) 25% of the optimal concentration of Long Ashton solution for cereals; (2) 25% macronutrient and optimal micronutrient concentration; (3) optimal macronutrient and 25% micronutrient concentration; and (4) optimal macronutrient and micronutrient concentrations.
Compared with the 25% base nutrient level, treatments supplemented with macronutrients reduced the number of viable vascular connections established by pre-germinated Striga seedlings as well as the total parasite biomass on the sorghum root system. Macronutrient treatment effects were observed across sorghum genotypes, independent of the presence and type of post-attachment resistance, but appeared to specifically improve mechanical resistance, hypersensitive and incompatibility responses before Striga reaches the host-root xylem.
This study demonstrates, for the first time, that nutrient availability drives Striga parasitism beyond the germination stages. Increased availability of nutrients, in particular macronutrients, enhances host-plant resistance in post-attachment stages, reinforcing the importance of current fertiliser recommendations.
smallholders, women and youth to benefit from SAI. While some tools and
processes are presented that may support this, there remains a challenge as to how such processes can be integrated into national policies and institutions.
with some proposing that only an ‘agroecological’ intensification pathway delivers sustainability. Others take a broader perspective arguing that all aspects of ecological, genetic, and socio-economic intensification need to be considered, but then assessed in terms of the sustainability of the outcomes. A major concern is that intensification that focuses on agricultural technology can lead to inequitable outcomes for women and poorer households, while agroecological intensification building upon local capitals is generally considered more equitable. Understanding the potential outcomes and inherent trade-offs of different approaches requires interdisciplinary research, evidence and decision-making tools, some examples of which are presented in this Special Issue
In all CA practices S. asiatica infection was significantly reduced. Best results were obtained with Stylosanthes guianensis (CAST). This species also suppressed ordinary weeds much better than other cover crops. With CAST, average parasite emergence was delayed by 7.5 days (in rice) and 6.3 days (in maize) and infection levels were reduced by 79% (in rice) and 92% (in maize) compared to the conventional farmer practice (CONV). NERICA varieties delayed S. asiatica emergence by 5.7 days (NERICA-9) and 9.7 days (NERICA-4) and reduced infection levels by 57% (NERICA-9) and 91% (NERICA-4) compared to B22. In maize the residual effect of resistance of NERICA-4 resulted in a delay of 7.5 days in S. asiatica emergence and a reduction of 60% in parasite numbers. The best combinations delay S. asiatica emergence by 17.8 days (CAST + NERICA-9) and 19.1 days (CARB + NERICA-4) and reduce the parasite infection levels by 96% (CAST + NERICA-9 or -4) to 98% (CARB + NERICA-4) in rice, compared to CONV + B22. After two full rice-maize rotation cycles S. asiatica seed numbers in the soil (0-10 cm) were 76% (CACM), 78% (CAST) and 86% (CARB) lower than under CONV. Even the combination of zero-tillage, crop residue mulching, cover crops and resistant rice varieties does not entirely prevent S. asiatica parasitism and seed bank increase. Additional measures, targeted to escaping weeds, would be required for fully effective and long-term control.